This directory contains the source files for the C component of XEmacs.
Nothing in this directory is needed for using XEmacs once it is built
and installed, if the dumped Emacs is copied elsewhere.
See the files ../README and then ../INSTALL for installation instructions.
Under Unix, the file `Makefile.in.in' is used as a template by the script
`../configure' to produce `Makefile.in'. The same script then uses `cpp'
to produce the machine-dependent `Makefile' from `Makefile.in';
`Makefile' is the file which actually controls the compilation of
Emacs. Most of this should work transparently to the user; you should
only need to run `../configure', and then type `make'.
General changes for XEmacs:
---------------------------
1. Lisp objects.
-- XFASTINT has been eliminated. Use of this expression as an lvalue
is incompatible with the union form of Lisp objects, and use as
an rvalue is likely to lead to errors and doesn't really save much
time. Expressions of the form `XFASTINT (obj) = num;' get replaced
by `obj = make_int (num);' or `XSETINT (obj, num);' and
expressions of the form `num = XFASTINT (obj);' get replaced by
`num = XINT (obj);'. Use Qzero in place of `make_int (0)'.
-- Use of XTYPE gets replaced by the appropriate predicate. Using
XTYPE only works for the small number of types that are not stored
using the Lisp_Record type (int, cons, string, and vector). For
example, `(XTYPE (foo) == Lisp_Buffer)' gets replaced by
`(BUFFERP (foo))'.
-- `XSET (obj, Lisp_Int, num)' gets replaced by `XSETINT (obj, num)',
for consistency.
-- Some occurrences of XSET need to get replaced by XSETR --
specifically, those where the type is not a primitive type
(primitive types are int, cons, string, and vector).
-- References to `XSTRING (obj)->size' get replaced with
`XSTRING_LENGTH (obj)'. This is currently for cosmetic reasons
but there may be other reasons in the future. (This change is
currently incomplete in the source files.)
2. Storage classes:
-- All occurrences of `const' should get replaced by CONST. This
is to work around a header conflict with X11R4.
-- All occurrences of `register' should be replaced by `REGISTER'.
It interferes with backtraces so we disable it if DEBUG_XEMACS
is defined.
3. Errors, messages, I18N3 snarfing:
-- Errors are continuable in XEmacs but are not in FSF Emacs.
Therefore, it's important that functions do something reasonable
if an error gets continued. If you want to signal a non-
continuable error, the call to Fsignal() gets put inside a
`while (1)' loop. To facilitate this, and also for proper I18N3
message snarfing, most calls to Fsignal() have been replaced by
calls to signal_error(), signal_simple_error(), etc. Look at
eval.c for a classification of various error functions.
-- Constant strings occurring in source files need to get wrapped
in a call to GETTEXT (or if inside of a call to `build_string',
change that function to `build_translated_string') if they don't
occur in certain places where the I18N3 message snarfer will see
them. For a complete discussion of this, see the file
lib-src/make-msgfile.lex.
NOTE: I18N3 support is not currently working, so the above may
or may not apply. Thus it is not a good idea to add random
GETTEXTs, unless you really know what you are doing.
-- Calls to `fprintf (stderr, ...)' and `printf (...)' get replaced
with calls to `stderr_out' and `stdout_out'. This is for I18N3
message snarfing.
4. Initialization:
-- FSF constructs like `obj = intern ("string"); staticpro (&obj);'
get replaced by `defsymbol (&obj);'. This is for code cleanness
and better purespace usage.
-- FSF constructs like
obj = intern ("error");
Fput (obj, Qerror_message, "message");
Fput (obj, Qerror_conditions, some list);
get replaced by calls to deferror(). See the definition of
deferror() for how the correct arguments to pass. This is for
code cleanness and I18N3 message snarfing.
-- Code in keys_of_foo() functions has been moved into Lisp.